What factors have contributed to climate change in the past and are they contributing to climate change now?
Author
Earth & Space Science
HS-ESS2-4Time: 5 Days
🌍 MYSTERY: Earth’s Climate Cycles 🌍
17.1 🔬 THE PHENOMENON
⚡ The amount of solar radiation hitting 65°N has been CYCLING UP AND DOWN for 750,000 years — repeating the same pattern every ~100,000 years! ⚡
17.1.1 🤔 THE BIG QUESTIONS:
🌀 Could natural cycles be causing today’s climate change?
🛸 How has Earth’s position in space changed over time?
🔥 What happens to Earth’s temperature when our orbit shifts?
18 Engage: Solar Radiation Patterns
18.1 Solar Radiation at 65°N
Connecting to our earlier questions about how Earth’s temperature has varied in the past, let’s analyze the total amount of energy from solar radiation reaching Earth at 65°N over the last 750,000 years.
viewof timeRange = Inputs.range([0,750], {step:50,value:750,label:"View last ___ thousand years:"})
Code
filteredRadData = radiationData.filter(d => d.kya<= timeRange)Plot.plot({title:"Summer Radiation at 65°N Over the Past "+ timeRange +",000 Years",subtitle:"Solar Radiation (Watts/m²)",width:750,height:400,x: {label:"Thousands of Years Ago (kya)",reverse:true},y: {label:"Radiation (W/m²)",domain: [420,550]},marks: [ Plot.ruleY([480], {stroke:"#999",strokeDasharray:"4,4"}), Plot.areaY(filteredRadData, {x:"kya",y:"radiation",y2:480,fill: d => d.radiation>480?"#e74c3c":"#3498db",fillOpacity:0.4}), Plot.line(filteredRadData, {x:"kya",y:"radiation",stroke:"#2c3e50",strokeWidth:2}), Plot.dot(filteredRadData.filter(d => d.radiation>520), {x:"kya",y:"radiation",fill:"red",r:5}), Plot.text(filteredRadData.filter(d => d.radiation>520), {x:"kya",y:"radiation",text: d =>"Peak",dy:-10,fontSize:10}) ]})
18.1.1 🎯 DETECTIVE MODE: What Do You See?
🔍 What repeating pattern jumps out at you in the last 750,000 years?
⏰ How often does the radiation peak?
🧊 Could this pattern explain Ice Ages?
🤯 WAIT — this pattern has been repeating for THREE-QUARTERS OF A MILLION YEARS?! Let’s find out WHY… 🤯
19 Explore: Earth’s Orbital Cycles
19.1 🎢 The THREE ORBITAL CYCLES
MISSION: Use these interactive models to gather evidence about Earth’s position in space. Could these orbital wobbles and stretches be causing the 100,000-year radiation pattern we just saw?
💡 DID YOU KNOW? In 1941, Serbian scientist Milutin Milankovitch figured out that Earth’s “wobbles” in space control Ice Ages. Mind = blown! 🤯
19.1.1 🔵 Cycle 1: ECCENTRICITY (~100,000 years)
THE STRETCH: Earth’s orbit changes from nearly circular ⭕ to more elliptical 🥚
THE SPIN: Earth’s axis wobbles like a spinning top 🌀 — changing which hemisphere points toward the Sun when we’re closest! This affects whether Northern or Southern summers are INTENSE.
19.2 🔬 INVESTIGATION LAB: Crack the Climate Code! 🕵️
⚡ TIME TO BECOME AN ORBITAL DETECTIVE! ⚡
19.2.1 🎒 Materials:
Graph paper or spreadsheet 📊
Colored pencils 🎨
Calculator 🧮
Your detective skills 🔍
19.2.2 📋 Mission Steps:
STEP 1: Analyze the Cycles 🌀
Use the interactive simulations above to explore each cycle
Record observations in your data table:
Cycle
Period
Current Value
Range
Climate Effect
Eccentricity
~100,000 yrs
0.017
0.0 - 0.06
Changes total radiation received
Obliquity
~41,000 yrs
23.5°
22.1° - 24.5°
Changes seasonal contrast
Precession
~23,000 yrs
N/A
360° rotation
Changes timing of seasons
STEP 2: Connect to the Data 📈
Go back and review that radiation graph from the beginning!
🎯 Which cycle’s period matches the big 100,000-year pattern?
🌊 Could the other two cycles explain the smaller “wiggles”?
STEP 3: Make Your Claim 🎤
📣 YOUR VERDICT: Do Earth’s orbital cycles CAUSE those radiation changes? Back it up with EVIDENCE from the models and data!
20 Explain: Connecting Orbit to Climate
🧊 THE MILLION-DOLLAR QUESTION 🧊
Did Earth’s orbital wobbles ACTUALLY cause Ice Ages? 🤔
20.1 🌍 THE SECRET MECHANISM REVEALED
💥 PLOT TWIST: It’s not about total yearly radiation — it’s about SUMMER radiation at 65°N (high northern latitudes)!
20.1.1 Why 65°N Matters:
Most of Earth’s land mass is in the Northern Hemisphere
Ice sheets grow when summer is NOT warm enough to melt winter snow
When summer radiation at 65°N is LOW, ice sheets expand
When summer radiation at 65°N is HIGH, ice sheets retreat
20.1.2 The Feedback Loop:
Low summer radiation → Snow persists → Ice sheets grow →
Higher albedo → More cooling → More ice growth
20.2 Comparing Radiation and Temperature
Code
combinedData = iceCoreTempData.map(d => {const rad = radiationData.find(r => r.kya=== d.kya);return {kya: d.kya,temp: d.temp,radiation: rad ? rad.radiation:480 };})Plot.plot({title:"Temperature vs. Summer Radiation at 65°N",width:750,height:400,x: {label:"Thousands of Years Ago",reverse:true},y: {label:"Temperature Anomaly (°C)",axis:"left"},marks: [ Plot.line(combinedData, {x:"kya",y:"temp",stroke:"#e74c3c",strokeWidth:2}), Plot.dot(combinedData.filter(d => d.temp>-2), {x:"kya",y:"temp",fill:"#e74c3c",r:6}), Plot.text([{x:350,y:2}], {x:"x",y:"y",text: d =>"Temperature",fill:"#e74c3c",fontSize:12}),// Add radiation trend for comparison (scaled to fit) Plot.line(combinedData, {x:"kya",y: d => (d.radiation-480) /10-6,stroke:"#3498db",strokeWidth:1,strokeDasharray:"4,2"}), Plot.text([{x:350,y:-5}], {x:"x",y:"y",text: d =>"Radiation (scaled)",fill:"#3498db",fontSize:10}) ]})
20.2.1 💡 Key Ideas: Earth-Sun Dynamics
Temperatures on Earth have fluctuated greatly during human history, marked by glacial and interglacial periods
A pattern exists in the frequency of these fluctuations (~100,000 years)
The pattern is explained by cyclical changes in Earth’s orbit shape and tilt
These changes cause ice sheets to expand and retreat
Current orbital parameters suggest Earth should be cooling, yet global temperatures are increasing
21 Elaborate: Solar Activity vs. Glacial Cycles
☀️ BUT WAIT… WHAT ABOUT THE SUN? ☀️
21.1 🔥 Solar Activity Data
🤔 NEW THEORY ALERT: Some people say the Sun itself is getting brighter, causing climate change. We know orbital wobbles caused Ice Ages… but what about the Sun’s OUTPUT? Let’s investigate! 🕵️
Code
solarData = [ {year:1880,tsi:1365.5,temp:-0.16}, {year:1900,tsi:1365.7,temp:-0.08}, {year:1920,tsi:1365.6,temp:-0.25}, {year:1940,tsi:1365.8,temp:0.12}, {year:1960,tsi:1365.9,temp:-0.01}, {year:1980,tsi:1366.1,temp:0.26}, {year:2000,tsi:1366.0,temp:0.42}, {year:2020,tsi:1361.0,temp:1.02}]Plot.plot({title:"Solar Output (TSI) vs Global Temperature",width:700,height:400,x: {label:"Year"},marks: [ Plot.line(solarData, {x:"year",y: d => (d.tsi-1360) *2,stroke:"#f1c40f",strokeWidth:2}), Plot.line(solarData, {x:"year",y: d => d.temp*3+5,stroke:"#e74c3c",strokeWidth:2}), Plot.text([{x:1900,y:12}], {x:"x",y:"y",text: d =>"Solar Output",fill:"#f1c40f",fontSize:12}), Plot.text([{x:1900,y:7}], {x:"x",y:"y",text: d =>"Temperature",fill:"#e74c3c",fontSize:12}) ]})
21.1.1 ✅ Analysis Questions
Has solar output increased significantly since 1980?
Has temperature increased significantly since 1980?
Can changes in solar output explain recent warming? Why or why not?
22 Evaluate: Are Orbital Factors Causing Warming Today?
🚨 THE FINAL VERDICT 🚨
So… are Earth’s orbital cycles causing climate change RIGHT NOW? 🌡️
22.1 📊 THE EVIDENCE SAYS…
Based on current orbital parameters:
Parameter
Current Value
Trend
Climate Effect
Eccentricity
0.017
Decreasing
Less seasonal variation
Obliquity
23.44°
Decreasing
Less extreme seasons
Precession
NH summer at aphelion
Changing slowly
Cooler NH summers
Conclusion: Based on Milankovitch cycles alone, Earth should be gradually cooling. The fact that Earth is warming despite this indicates another factor is at play.
This sets up our next investigation: What IS causing the warming?
22.2 🎮 CHALLENGE MODE: Test Your Knowledge! 🏆
🔥 Can you ace this quiz? Let’s find out! 🔥
Code
quizData = [ {question:"What is the approximate period of the eccentricity cycle?",options: ["23,000 years","41,000 years","100,000 years","1 million years"],correct:2,feedback: {correct:"🎉 YES! The eccentricity cycle takes about 100,000 years, which matches the major Ice Age pattern we saw in the data!",wrong:"❌ Not quite! Remember, the eccentricity cycle is the LONGEST of the three Milankovitch cycles. It takes about 100,000 years!" } }, {question:"Why is summer radiation at 65°N latitude so important for ice ages?",options: ["It's where most people live","It's where most land mass is located, and ice sheets need cool summers to persist","The Sun is closest to Earth at this latitude","Ocean currents are strongest here" ],correct:1,feedback: {correct:"💯 PERFECT! Most land is in the Northern Hemisphere. When summers are cool at 65°N, snow doesn't melt and ice sheets GROW!",wrong:"❌ Think about it: Where is most of Earth's land? And what happens if summer isn't warm enough to melt winter snow?" } }, {question:"Earth's current axial tilt is approximately:",options: ["22.1°","23.5°","24.5°","45°"],correct:1,feedback: {correct:"✅ Spot on! Earth currently tilts at 23.5° — right in the middle of its range!",wrong:"❌ Close! Earth's tilt right now is 23.5°, which is about halfway between the minimum (22.1°) and maximum (24.5°)." } }, {question:"According to Milankovitch cycles, what should Earth's climate be doing right now?",options: ["Warming rapidly","Staying constant","Cooling gradually","Experiencing an ice age"],correct:2,feedback: {correct:"🧠 SMART! Based on orbital cycles alone, Earth should be cooling slightly. But it's warming instead — which means something ELSE is going on!",wrong:"❌ Actually, our orbital parameters suggest we should be cooling gradually. But we're warming instead... 🤔 Something else must be causing it!" } }, {question:"What causes the ~100,000 year glacial-interglacial cycle?",options: ["Changes in the Sun's energy output","Volcanic activity","Changes in Earth's orbital eccentricity","Human activity" ],correct:2,feedback: {correct:"🌟 EXCELLENT! Eccentricity — the shape of Earth's orbit — drives the major 100,000-year cycle!",wrong:"❌ Nope! The 100,000-year cycle matches the eccentricity cycle — when Earth's orbit becomes more or less elliptical!" } }, {question:"The precession cycle affects climate by:",options: ["Changing total solar radiation received","Changing which season occurs at perihelion vs aphelion","Changing Earth's distance from the Sun","Changing the Sun's output" ],correct:1,feedback: {correct:"🎯 NAILED IT! Precession changes WHEN (which season) Earth is closest to the Sun, making some hemispheres' summers more intense!",wrong:"❌ Think about what 'wobble' means — precession changes which SEASON happens when Earth is closest to or farthest from the Sun!" } }, {question:"If Earth's axial tilt increased to 24.5°, seasons would become:",options: ["Less extreme","More extreme","Unchanged","Reversed"],correct:1,feedback: {correct:"💪 YES! Greater tilt = more extreme seasons. Summer gets HOTTER, winter gets COLDER!",wrong:"❌ Remember: Greater tilt means the Northern Hemisphere points MORE toward (or away from) the Sun, making seasons more extreme!" } }, {question:"What is the significance of global warming occurring despite Milankovitch cycles predicting cooling?",options: ["Milankovitch cycles are wrong","Another factor must be causing the warming","The Sun's output has increased dramatically","Earth's orbit has changed unexpectedly" ],correct:1,feedback: {correct:"🔥 GENIUS! You got it! Orbital cycles say we should cool, but we're warming — so something NEW and POWERFUL must be at work!",wrong:"❌ The cycles aren't wrong — they've worked for hundreds of thousands of years! The fact that we're warming ANYWAY means a NEW factor is involved..." } }]